Bug fix: Appending partitions 5 to 8 caused damaged ISO filesystems if not for SUN disk label

libisofs/ecma119.c

@@ -4601,13 +4601,13 @@ ex: /* LIBISO_ALLOC_MEM failed */
 }
 
 
-/* Obtains start and end number of appended partition range and returns
-   the number of valid entries in the list of appended partitions.
+/* Determines the range of valid partition numbers depending on partition
+   table type.
 */
-int iso_count_appended_partitions(Ecma119Image *target,
-                                  int *first_partition, int *last_partition)
+void iso_tell_max_part_range(Ecma119Image *target,
+                             int *first_partition, int *last_partition)
 {
-    int sa_type, i, count= 0;
+    int sa_type;
 
     sa_type = (target->system_area_options >> 2) & 0x3f;
     if (sa_type == 3) { /* SUN Disk Label */
@@ -4617,6 +4617,18 @@ int iso_count_appended_partitions(Ecma119Image *target,
         *first_partition = 1;
         *last_partition = 4;
     }
+}
+
+
+/* Obtains start and end number of appended partition range and returns
+   the number of valid entries in the list of appended partitions.
+*/
+int iso_count_appended_partitions(Ecma119Image *target,
+                                  int *first_partition, int *last_partition)
+{
+    int i, count= 0;
+
+    iso_tell_max_part_range(target, first_partition, last_partition);
     for (i = *first_partition - 1; i <= *last_partition - 1; i++) {
         if (target->opts->appended_partitions[i] == NULL)
     continue;

libisofs/ecma119.h

@@ -1,6 +1,6 @@
 /*
  * Copyright (c) 2007 Vreixo Formoso
- * Copyright (c) 2009 - 2018 Thomas Schmitt
+ * Copyright (c) 2009 - 2019 Thomas Schmitt
  *
  * This file is part of the libisofs project; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License version 2 
@@ -1055,4 +1055,10 @@ int iso_interval_reader_start_size(Ecma119Image *t, char *path,
 int iso_count_appended_partitions(Ecma119Image *target,
                                   int *first_partition, int *last_partition);
 
+/* Determines the range of valid partition numbers depending on partition
+   table type.
+*/
+void iso_tell_max_part_range(Ecma119Image *target,
+                             int *first_partition, int *last_partition);
+
 #endif /*LIBISO_ECMA119_H_*/

libisofs/system_area.c

@@ -153,8 +153,10 @@ static int compute_partition_size(Ecma119Image *t, char *disk_path,
 int iso_compute_append_partitions(Ecma119Image *t, int flag)
 {
     int ret, i, sa_type, cyl_align, cyl_size = 0;
+    int first_partition, last_partition;
     uint32_t pos, size, add_pos = 0;
     off_t start_byte, byte_count;
+    char msg[80];
 
     sa_type = (t->system_area_options >> 2) & 0x3f;
     cyl_align = (t->system_area_options >> 8) & 0x3;
@@ -176,11 +178,20 @@ int iso_compute_append_partitions(Ecma119Image *t, int flag)
 
 #endif
 
+    iso_tell_max_part_range(t, &first_partition, &last_partition);
     for (i = 0; i < ISO_MAX_PARTITIONS; i++) {
         if (t->opts->appended_partitions[i] == NULL)
     continue;
         if (t->opts->appended_partitions[i][0] == 0)
     continue;
+        if (i + 1 > last_partition || i + 1 < first_partition) {
+            sprintf(msg,
+         "Partition number %d of appended partition is out of range [%d - %d]",
+                    i + 1, first_partition, last_partition);
+            iso_msgs_submit(0, msg, 0, "FAILURE", 0);
+            return ISO_BAD_PARTITION_NO;
+        }
+
         ret = compute_partition_size(t, t->opts->appended_partitions[i], &size,
                                      t->opts->appended_part_flags[i]);
         if (ret < 0)
@@ -1862,10 +1873,8 @@ int iso_write_system_area(Ecma119Image *t, uint8_t *buf)
     memset(buf, 0, 16 * BLOCK_SIZE);
 
     sa_type = (t->system_area_options >> 2) & 0x3f;
-    if (sa_type == 3) {
-        first_partition = 2;
-        last_partition = 8;
-    }
+
+    iso_tell_max_part_range(t, &first_partition, &last_partition);
     for (i = first_partition - 1; i <= last_partition - 1; i++)
         if (t->opts->appended_partitions[i] != NULL) {
             will_append = 1;
@@ -3190,20 +3199,14 @@ static int partappend_writer_write_vol_desc(IsoImageWriter *writer)
 static int partappend_writer_write_data(IsoImageWriter *writer)
 {
     Ecma119Image *target;
-    int res, first_partition = 1, last_partition = 0, sa_type;
+    int res, first_partition = 1, last_partition = 0;
     int i;
 
     target = writer->target;
 
     /* Append partition data */
-    sa_type = (target->system_area_options >> 2) & 0x3f;
-    if (sa_type == 0) { /* MBR */
-        first_partition = 1;
-        last_partition = 4;
-    } else if (sa_type == 3) { /* SUN Disk Label */
-        first_partition = 2;
-        last_partition = 8;
-    }
+    iso_tell_max_part_range(target, &first_partition, &last_partition);
+    
     for (i = first_partition - 1; i <= last_partition - 1; i++) {
         if (target->opts->appended_partitions[i] == NULL)
     continue;